CVE-2026-23327

HIGHNVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2026-03-25. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
7.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.1Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

cxl/mbox: validate payload size before accessing contents in cxl_payload_from_user_allowed()

cxl_payload_from_user_allowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with an undersized payload (ie: 1 byte for CXL_MBOX_OP_CLEAR_LOG, which expects a 16-byte UUID), uuid_equal() reads past the allocated buffer, triggering a KASAN splat:

BUG: KASAN: slab-out-of-bounds in memcmp+0x176/0x1d0 lib/string.c:683 Read of size 8 at addr ffff88810130f5c0 by task syz.1.62/2258

CPU: 2 UID: 0 PID: 2258 Comm: syz.1.62 Not tainted 6.19.0-dirty #3 PREEMPT(voluntary) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xab/0xe0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xce/0x650 mm/kasan/report.c:482 kasan_report+0xce/0x100 mm/kasan/report.c:595 memcmp+0x176/0x1d0 lib/string.c:683 uuid_equal include/linux/uuid.h:73 [inline] cxl_payload_from_user_allowed drivers/cxl/core/mbox.c:345 [inline] cxl_mbox_cmd_ctor drivers/cxl/core/mbox.c:368 [inline] cxl_validate_cmd_from_user drivers/cxl/core/mbox.c:522 [inline] cxl_send_cmd+0x9c0/0xb50 drivers/cxl/core/mbox.c:643 __cxl_memdev_ioctl drivers/cxl/core/memdev.c:698 [inline] cxl_memdev_ioctl+0x14f/0x190 drivers/cxl/core/memdev.c:713 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xa8/0x330 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fdaf331ba79 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fdaf1d77038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fdaf3585fa0 RCX: 00007fdaf331ba79 RDX: 00002000000001c0 RSI: 00000000c030ce02 RDI: 0000000000000003 RBP: 00007fdaf33749df R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fdaf3586038 R14: 00007fdaf3585fa0 R15: 00007ffced2af768

Add 'in_size' parameter to cxl_payload_from_user_allowed() and validate the payload is large enough.

CVSS v3
7.1
EG Score
7.1(medium)
EPSS
2.5%
KEV
Not listed

Published

March 25, 2026

Last Modified

June 1, 2026

References (3)

Vendor Advisories for CVE-2026-23327(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.19.7—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Data Freshness Timeline

(refreshed 0× in last 7d / 0× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
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  1. 2026-06-28 04:56 UTCEPSS rescore
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  27. 2026-06-11 23:32 UTCEG score recompute
  28. 2026-06-11 23:32 UTCGHSA enrichment
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  31. 2026-06-10 16:07 UTCEG score recompute
  32. 2026-06-10 16:07 UTCGHSA enrichment
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  35. 2026-06-10 04:08 UTCGHSA enrichment
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  39. 2026-06-08 14:33 UTCGHSA enrichment
  40. 2026-06-08 14:17 UTCEPSS rescore
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  43. 2026-06-08 01:07 UTCGHSA enrichment
  44. 2026-06-07 15:25 UTCEPSS rescore
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  46. 2026-06-07 12:34 UTCEG score recompute
  47. 2026-06-07 12:34 UTCGHSA enrichment
  48. 2026-06-06 13:47 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2026-23327?
CVE-2026-23327 is a high vulnerability published on March 25, 2026. In the Linux kernel, the following vulnerability has been resolved: cxl/mbox: validate payload size before accessing contents in cxlpayloadfromuserallowed() cxlpayloadfromuserallowed() casts and dereferences the input payload without first verifying its size. When a raw mailbox command is sent with…
When was CVE-2026-23327 disclosed?
CVE-2026-23327 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on June 1, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23327 actively exploited?
CVE-2026-23327 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23327?
CVE-2026-23327 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-23327?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23327, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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